UFRGS,
May 25, 2010
The Outer Surface, Ultra-thin layers and Contacts studied by
High-Sensitivity LEIS
Hidde H. Brongersma
Eindhoven University of Technology, Eindhoven, The Netherlands
ION-TOF GmbH, Münster, Germany and Tascon GmbH, Münster, Germany
Hidde.Brongersma@iontof.com
In modern technology new (sub-) nanometer materials and preparation techniques are being
developed. Advancement relies heavily on the availability of analytic techniques that can validate
and support the preparation. Introducing the Qtac100, a new high-sensitivity Low Energy Ion
Scattering (LEIS) instrument, a range of new applications for this extremely surface sensitive
analytical technique becomes available.
The outermost atoms of a surface largely control processes such as catalysis, adhesion, electron
emission and growth. While analytic tools (such as XPS) probe an average of many atomic layers,
LEIS can selectively analyze the outer atoms. This greatly simplifies the quantification. In addition,
non-destructive depth profiling (0 – 10 nm), increased sensitivity for the light elements and improved
mass resolution for the heavier elements are now possible. HS-LEIS is just as well suited for the
quantitative analysis of amorphous, insulating and extremely rough surfaces as for flat single
crystals. This has opened many new applications for catalysts, growth, microelectronics, adhesion,
diffusion, etc.
After an introduction of the technique, the focus will be on applications where valuable information
has been obtained that is impossible (very difficult) to obtain with other analytical techniques. The
new possibilities will be illustrated with a selection of examples from:
Catalysis
Growth
- surface segregation
- ALD growth
- site of poison
- coverage
- promoters
- nucleation
- isotopic exchange
- pinholes
- cluster: size; core/shell
Microelectronics
Polymers
- interface diffusion
- pinholes
- high-k dielectrics
- interface diffusion
- plasma modification
- metal-polymer diff.
- SAMs
- bio sensors
- (anti-) wetting
The findings will be compared and contrasted to those obtained by analytic techniques such as XPS,
ToF-SIMS, AFM/STM, conventional LEIS.
----------------------------